An UMTS (Universal Mobile Telecommunication System) network includes a core network of various elements and also a radio access network, called UTRAN (UMTS terrestrial radio access network). A UTRAN includes radio network controllers (RNCs) that control so-called Node Bs, that in turn wirelessly communicate with UE (user equipment) devices, i.e. e.g. mobile phones. UMTS networks are provided and operated as specified by 3GPP (Third Generation Partnership Program) specifications, which are evolving, and which are issued in successive releases.
In the most current evolution, which will issue as release 6, a proposal has been made for a fast Node B controlled scheduling mechanism requiring both the UE and the Node B to individually maintain a data rate pointer indicating the maximum uplink data rate allowed for use by the UE; the data rate actually used (any rate up to and including the rate pointed to by the data rate pointer in communicating with the Node B) is indicated in a transport format combination indicator (TFCI) data object sent by the UE to the Node B. The data rate pointer is updated according to the prior art using differential signalling (increase/decrease); a Node B command to change the current value of the data rate pointer is a command to increase or decrease the data rate pointer, i.e. to change by a step the data rate that is pointed to by the data rate pointer, so as to point to the next higher or lower allowed data rate in a set of data rates known as a TFCS (transport format combination set). (A UE can only request a change of the data rate pointer—using rate request signalling—and the Node B is in control; if it finds a rate request from a UE acceptable, it updates its own pointer entity and signals a rate grant to the UE. If the Node B determines that no change should be made to the data rate pointer, it can indicate so using discontinuous (DTX) signaling or by some other signalling.)
Now in a typical case, initially a UE device is not transmitting data to a Node B, but then data arrives from an application hosted by the UE device and is stored in a transmission buffer within the UE device. If the UE then has a lot of data to transmit and the network could allow it to transmit at a high target data rate but the data rate pointer is set at a low value (or zero), getting to the high target data rate takes several rate request/rate grant cycles, each incrementing the data rate pointer by one step. Such a ramping up can be a relatively slow process and could be seen as sub-optimal usage of uplink resources, causing longer than necessary delays to the end users.
Thus, what is needed—at least in some situations—is a mechanism for changing a UE data rate pointer from a low value to a high value faster than can be done using repeated increments of a single step.